The electromagnetic contact device 1 shown in FIG. 13 comprises a lower case 3 and upper case 4, formed from a synthetic resin material having insulating properties. In the upper case 4 are fixed terminal portions 10a to 10d each having contact points and a coil terminal 11 of an electromagnet, and in addition, a contact portion comprising movable contact points and fixed contact points is accommodated in an extinction chamber within the upper case 4. The lower case 3 accommodates an electromagnet and a driving lever which drive the contact portion. Further, within the upper case 4 are mounted an extinction cover 5 which covers the contact point portion in the extinction chamber, and a terminal cover 6 which covers the terminal portions 10a to 10d, each having contact points, and the coil terminal 11 of the electromagnet.
Here, when an abnormally large current flows in the contact portion of the electromagnetic contact device 1 due to a short-circuit accident or similar, there is the concern that the extinction cover 5 may fly off due to the rise in internal pressure in the extinction chamber due to the arc gas which is generated. Hence, electromagnetic contact devices are known in which, by providing a gas escape hole in a portion of the extinction cover and allowing the generated arc gas to be released to the outside from the gas escape hole, the rise in internal pressure of the extinction chamber is suppressed, and flying-off of the extinction cover 5 is prevented (see for example Patent Reference 1).    Patent Reference 1: Japanese Patent Laid-open No. 2005-332588